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 Post subject: Problem with ground or antenna wire? - crystal radio
PostPosted: May Sat 14, 2022 8:54 am 
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Joined: Apr Thu 28, 2022 10:55 am
Posts: 29
Location: Australia
Hi my antenna worked perfectly fine connecting to the shed but I decided to connect one to my second story window, the shed antenna and ground are both linked to the window of my house. I've come over a problem after installing the new wires to the house, when ever I plug in my crystal radio in my house I can only hear around 1-2 stations, the ABC news station seems to overpower the other stations. But when I bring the crystal radio down to the shed and plug it in I can hear around 4-5 stations. does anyone know why. I replaced the copper antenna and ground wire linking from the house to the shed with insulated wire but that didn't solve the problem?("the copper wire connecting from the veranda to the shed is not insulated but the parts that touch the veranda and the shed are insulated") I also only use one radio, I don't have two radios plugged in at once. I have also discovered when I touch the washer connecting the diode to the earphone, capacitor and resistor in the house I can hear all the channels at once, but when I am in the shed and touch the same washer the sound cancels out? any ideas?


Attachments:
File comment: the diagram of my house with the wires
image_2022-05-14_174842374.png
image_2022-05-14_174842374.png [ 311.16 KiB | Viewed 344 times ]
File comment: the diagram of my radio
image_2022-05-14_175053927.png
image_2022-05-14_175053927.png [ 22.62 KiB | Viewed 344 times ]

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 Post subject: Re: Problem with ground or antenna wire? - crystal radio
PostPosted: May Sat 14, 2022 11:33 am 
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Joined: Feb Mon 11, 2019 10:21 pm
Posts: 30
My thought would be that you increased the length of both your antenna and ground. I have a 490ft long wire antenna here with two different length feed lines to the radio with a relay between them. I can listen on either feed line and it completely changes the tune of the radio by increasing or decreasing the antenna length. I can often hear different stations on each feed line.


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 Post subject: hi 34sparton
PostPosted: May Sat 14, 2022 11:55 am 
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Joined: Apr Thu 28, 2022 10:55 am
Posts: 29
Location: Australia
Is there any way i can get more radio channels connecting to the house then ? do i have to increase the antenna length connecting to the house, and that will increase the overall antenna length since the shed antenna and the house antenna are connected?

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 Post subject: Re: Problem with ground or antenna wire? - crystal radio
PostPosted: May Sat 14, 2022 12:16 pm 
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Joined: Feb Mon 11, 2019 10:21 pm
Posts: 30
You will probably have to experiment with antenna lengths. You might try making your house ground as short as possible. In my case my radio equipment is all in a building on the rear of my property and well away from the house. I do hear more there being away from the electrical noise of the house. By the way all my antennas are built from insulated 14 ga thhn wire so the insulated wire that you ran to the house is acting as part of your antenna. Good luck!


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 Post subject: Re: Problem with ground or antenna wire? - crystal radio
PostPosted: May Sat 14, 2022 3:12 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 17709
Location: S. Dartmouth MA 02748-1225 USA
The Zig-Zag arrangement is canceling itself out...

I will be honest, your antenna looks a lot like one I created when I first got started at 12yo. Lots of wire, every which way, it did not work...

I would:

Decide which location is better suited for radio operation, I am assuming it is the red boxes, choose one...

Then choose the farthest , high mount point for the far end as high and as safely as possible.
Chose the other end such that, in the building arrangement, permits the far antenna wire to pass over the point where the radio is. Anchor at that point and fasten a "downlead" at that end.

Never place the antenna above or below power lines...

For BC band it is better advantage to have some height to the antenna wire as the vertical wire does a lot of pickup as well so long as it is 90 degree as much as possible to the horizontal wire.

DO use glass or porcelain insulators for the ends of the antenna, fasten the down lead with a small bronze clamp. The highest voltage on an antenna is at the ends, so any leakage, poor insulators, dirty insulators is important for a crystal set. Avoid plastic, it has an electrostatic attraction for dust. If you are stuck for antenna insulators PM me... There are compression type or strain type. If a strain insulator breaks, the antenna will fall but strain type has longest leakage path. A compression type never seems to break and the loops hold it together, but the leakage path is short and they are somewhat hard to clean. Compression insulators are better for guy wires...

Change the ground rod to as near to earth and the "window" location of the radio. DO buy an 8 foot rod, it will be hard to drive in depending on how far from the foundation of the house, usually some 3' away will be clear of the concrete footing WARNING if even the slightest doubt that there is buried utilities call DIG-SAFE and find out...

That "new" ground rod can be driven below grade and attached using bronze electrical clamps #10 or larger wire and bury too. Direct the larger ground wire to the wall of house that wire can be now changed in size to a smaller easier to manage ground wire, use another bronze clamp and run as direct as possible to the window entrance. Do keep this ground arrangement as short as possible.

Do not connect either the ground or the antenna download to anything else except a lightning arrestor and the radio...

Those bronze clamps can be coated with asphalt roofing cement for weather protection. "Tar" coating can be cleaned off later if need be and will last some 10 or more years.

Those bronze clamps are called "Burndy" or "Burndies"

Attachment:
Burndy clamp.jpeg
Burndy clamp.jpeg [ 22.14 KiB | Viewed 295 times ]


Burndies come in ALL sizes, small for two/three #18 wires up to two #0000 cables, yes I have installed Burndies on mill "cleat" lines. Its an all day project for a three phase line... The big Burndies require 24's (24" wrenches) to tighten :roll:

Antenna installations should not be soldered, soldering anneals the copper and makes a weak point where the antenna will stretch and break.

Ideally, antenna wire for receiving or low power transmitter is between #14 to #18 ga hard drawn strand (usually 7 strands).

------------------------------------------------------------------------------------------------------

There are at least two "things" going on that are causing reception of one station all over the dial. The crystal set selectivity is poor, combined with the strong signal. To reduce the strong signal a "Wave Trap" is used, it is a tuned circuit that is either put in series or parallel and can be series or parallel in configuration. Generally it is made from an inductor and a variable condenser that can tune the all or a portion of the radio band desired, just like a crystal set does, but the coil is given consideration design for high "Q"... Once the wave trap is connected, it is tuned to reduce the offending signal. The wave trap does reduce the overall signal but the reduction of the offending signal is significant.

I advise learning how to make more efficient coils, in any style you choose. Do look carefully at the use of litz wire, it is pricey, hard to terminate and effectiveness over solid wire is marginal Often, litz wire coils are the last step in efficiency in a crystal set.

GL

Chas

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 Post subject: Re: Problem with ground or antenna wire? - crystal radio
PostPosted: May Sat 14, 2022 3:20 pm 
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Joined: Apr Thu 28, 2022 10:55 am
Posts: 29
Location: Australia
thank you Chas, i will make sure to try some of the things you have said, thank you for the help!! :D

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 Post subject: Re: Problem with ground or antenna wire? - crystal radio
PostPosted: May Sat 14, 2022 8:09 pm 
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Joined: Jan Sat 25, 2020 5:23 am
Posts: 1037
Location: Colorado Springs, CO 80917
Not really an antenna suggestion but...
it seems to me that it would be worth trying to disconnect one end of the coil (see picture). My reasoning being that, in your schematic, there's always part of the coil that is connected to a "short", and that probably loads the whole tuned circuit down & lowers Q as well.

I assume there's some significance to the schematic parts being in red?


Attachments:
xtal radio suggestion temp.jpg
xtal radio suggestion temp.jpg [ 38.38 KiB | Viewed 266 times ]
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 Post subject: Re: Problem with ground or antenna wire? - crystal radio
PostPosted: May Sun 15, 2022 12:55 am 
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Joined: Apr Thu 28, 2022 10:55 am
Posts: 29
Location: Australia
hi hwhall, a user "Eickerman" helped me add some stuff to this circuit that why they are in red, i also thought about removing the smaller coil since it seems like the large coil does nothing. where would I connect the two end of a single large coil though, since the large coil on the current designs are connected to multiple places and the smaller coils are connected to the antenna? the large coil is around 166 turn 21 gauge wire with a diameter of 1.5 inches, and the smaller coil is 58 turn with the same diameter and gauge wire as the large. thanks the large coil is around 166


Attachments:
File comment: how the radio looks like
image_2022-05-15_095919462.png
image_2022-05-15_095919462.png [ 743.37 KiB | Viewed 239 times ]

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 Post subject: Re: Problem with ground or antenna wire? - crystal radio
PostPosted: May Sun 15, 2022 4:14 am 
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Joined: Jan Sat 25, 2020 5:23 am
Posts: 1037
Location: Colorado Springs, CO 80917
Ahhh... I see that this is the same radio you were working on in this thread:
viewtopic.php?f=12&t=412313

The ARF rules are that we are supposed to stick to one thread per radio so that all the questions, answers, changes, etc., are visible to people who might want to help out.


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 Post subject: Re: Problem with ground or antenna wire? - crystal radio
PostPosted: May Sun 15, 2022 4:55 am 
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Joined: Apr Thu 28, 2022 10:55 am
Posts: 29
Location: Australia
i see hwhall, well this thread was about the antenna i have installed, than the last couple post including my old radio.

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 Post subject: Re: Problem with ground or antenna wire? - crystal radio
PostPosted: May Sun 15, 2022 4:58 am 
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Joined: Jan Sat 25, 2020 5:23 am
Posts: 1037
Location: Colorado Springs, CO 80917
Quote:
thought about removing the smaller coil since it seems like the large coil does nothing

Why would you remove the smaller (shorter) coil if the larger coil does nothing?? Perhaps you meant that the *smaller coil* seems to be doing nothing.

The smaller coil is supposed to be the antenna coupling coil. Normally it is able to be moved closer to, and further away from, the larger (longer) coil. It looks like yours is not movable. It probably doesn't seem to do much, does it?

The larger (longer) coil is part of the tuned circuit (along with the variable capacitor) that selects the frequency you want to hear. Moving the slider (or "tap") along the long coil allows the capacitor to tune different ranges of frequency (also, the same frequency can be tuned in by different combinations of coil tap & capacitor settings). If adjusting the slider along the longer coil doesn't affect tuning ("does nothing") then something is very likely wrong with the way you put the parts together.

One of the attached pictures has a couple of questions about the construction.

Quote:
where would I connect the two end of a single large coil though


I think I would try doing it like the attached schematic. The antenna connected to the tuned circuit directly.


Attachments:
xtal radio questions temp.jpg
xtal radio questions temp.jpg [ 345 KiB | Viewed 206 times ]
xtal radio suggestion 2 temp.jpg
xtal radio suggestion 2 temp.jpg [ 34.52 KiB | Viewed 206 times ]
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 Post subject: Re: Problem with ground or antenna wire? - crystal radio
PostPosted: May Sun 15, 2022 5:07 am 
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Joined: Jan Sat 25, 2020 5:23 am
Posts: 1037
Location: Colorado Springs, CO 80917
Quote:
well this thread was about the antenna i have installed, than the last couple post including my old radio.


Well, that IS one way of looking at it. Or one could think of it as the same radio with different antennas. :D


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 Post subject: Re: Problem with ground or antenna wire? - crystal radio
PostPosted: May Sun 15, 2022 6:04 am 
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Joined: Apr Thu 28, 2022 10:55 am
Posts: 29
Location: Australia
the connection point to the slider you asked was originally soldered down but i had to bend the slider a bit more so i had to remove the solder, i am going to re-solder it. and those two circles in the image are the sliders. thanks for the new schematics for the radio i will try it out!. if you want i can sends you pictures of the left side of the radio and the connection points. thank you.

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 Post subject: Re: Problem with ground or antenna wire? - crystal radio
PostPosted: May Sun 15, 2022 7:31 am 
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Joined: Apr Thu 28, 2022 10:55 am
Posts: 29
Location: Australia
hwhall wrote:
Quote:
thought about removing the smaller coil since it seems like the large coil does nothing

Why would you remove the smaller (shorter) coil if the larger coil does nothing?? Perhaps you meant that the *smaller coil* seems to be doing nothing.

The smaller coil is supposed to be the antenna coupling coil. Normally it is able to be moved closer to, and further away from, the larger (longer) coil. It looks like yours is not movable. It probably doesn't seem to do much, does it?

The larger (longer) coil is part of the tuned circuit (along with the variable capacitor) that selects the frequency you want to hear. Moving the slider (or "tap") along the long coil allows the capacitor to tune different ranges of frequency (also, the same frequency can be tuned in by different combinations of coil tap & capacitor settings). If adjusting the slider along the longer coil doesn't affect tuning ("does nothing") then something is very likely wrong with the way you put the parts together.

One of the attached pictures has a couple of questions about the construction.

Quote:
where would I connect the two end of a single large coil though


I think I would try doing it like the attached schematic. The antenna connected to the tuned circuit directly.


I've tried the circuit mentioned here with the antenna connecting to my house and I just get static with one channel in the background, its not too loud but the static is quite loud? this radio has been causing quite a lot of problems, I've been thinking about just making a whole new radio a better one than this. I still got to fix the antenna problem, the one linking to my house that is connected to the shed antenna i made. if i can't find a fix for that i will probably just make one straight long antenna going to my window and then instead of the ground wire connecting to the shed ground i will connect it to the faucet two stories down my house window which is closer by a few meters if that will change anything. if you have any good crystal radio schematics can you please share them here viewtopic.php?f=1&t=412482 they don't necessarily have to be massive like the title is on that post. thanks :D

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 Post subject: Re: Problem with ground or antenna wire? - crystal radio
PostPosted: May Sun 15, 2022 7:44 am 
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Joined: Jan Sat 25, 2020 5:23 am
Posts: 1037
Location: Colorado Springs, CO 80917
Quote:
with the antenna connecting to my house


I think you mean when you bring the radio into the house & then connect to the outdoor antenna array that you diagrammed earlier. If you don't hear all that "static" when the radio is out in the other building (shed?) then I think you just have a very noisy environment in the house. It may not be the fault of the radio at all.

Crystal radios, like most really simple electronics designs, often are "finicky" and sometimes difficult to get working right. The antenna and ground are sometimes critical to achieving good results. But we know from the experience of others that it is possible to get one working rather well.

EDIT: BTW, when I was tinkering with some crystal set designs, I did find that indoors was very noisy and any time that either the antenna or ground lead contacted a heater duct or window frame, radio noise was intense.


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 Post subject: Re: Problem with ground or antenna wire? - crystal radio
PostPosted: May Sun 15, 2022 8:47 am 
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Joined: Apr Thu 28, 2022 10:55 am
Posts: 29
Location: Australia
hwhall wrote:
Quote:
with the antenna connecting to my house


I think you mean when you bring the radio into the house & then connect to the outdoor antenna array that you diagrammed earlier. If you don't hear all that "static" when the radio is out in the other building (shed?) then I think you just have a very noisy environment in the house. It may not be the fault of the radio at all


yeah that most likely is the problem to why i get less channels with the old design of the radio when i am in the house, next time i build a radio it most likely wont have two coils like that since the large one did nothing with the original schematics posted in this thread, unless i can find one that actually uses both coils. thanks for all the help hwhall :D !!

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